(a) Field of the Invention
The present invention relates to a thin film transistor array panel and a manufacturing method thereof.
(b) Description of the Related Art
A thin film transistor is used as a switching element to independently drive a pixel in a flat display device such as a liquid crystal display or an organic light emitting device. A flat display devices will include a thin film transistor array panel in which each thin film transistor is connected to signal lines, such as a scanning signal line (or a gate line) for transmitting a scanning signal to the thin film transistor, and a data line for transmitting a data signal to the thin film transistor. Each thin film transistor is also connected to a pixel electrode.
The signal lines extend along the length of the thin film transistor array panel, such that it is necessary to form the signal line with a material having low resistivity. Accordingly, copper (Cu), which has a low resistivity is used as the material to form the signal line.
A passivation layer is typically deposited on the signal line, such as the data line, and the passivation layer has a contact hole so that the underlying signal line can contact a different layer that is over the passivation layer. The passivation layer may be made of an organic layer or an inorganic layer. When the passivation layer is made of an inorganic layer, a photosensitive film is coated on the inorganic layer to form the contact hole, while when the passivation layer is made of an organic layer, an ashing process using oxygen gas is further required after forming the contact hole by using the organic layer as a mask.
However, in forming the contact hole in the passivation layer, or performing the ashing process, foreign particles may be generated at the surface of the signal line which include copper, and the color of the signal line is changed, indicating contamination of the surface, such that the contact characteristic is deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.